The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 23, 1993
Filed:
Sep. 10, 1991
Morimasa Kuragano, Sakai, JP;
Takeshi Isobe, Takaishi, JP;
Nobutaka Ueda, Takaishi, JP;
Minoru Koshibe, Sakai, JP;
Yoshihiro Sezaki, Izumi, JP;
Hirozo Segawa, Niigata, JP;
Katsuji Yoguchi, Niigata, JP;
Rensuke Ikarashi, Niigata, JP;
Mitsui Toatsu Chemicals, Incorporated, Tokyo, JP;
Kuraray Co., Ltd., Kurashiki, JP;
Abstract
A process is provided for the purification of methacrylic acid. The process can easily remove dibasic acids and aldehydes containing in trace amounts as impurities. According to the process, crude methacrylic acid obtained as an aqueous solution by vapor-phase catalytic oxidation of isobutylene, tertiary butanol, methacrolein or isobutyl aldehyde is treated with at least one compound selected from the group consisting of m-aminophenol, m-phenylenediamine, 2,4-diaminotoluene and 2,4-diamino-diphenylamine, followed by distillation, optionally, in the presence of a p-phenylene diamine.